package com.hmdp.utils;

import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Component;

import java.time.LocalDateTime;
import java.time.ZoneOffset;
import java.time.format.DateTimeFormatter;

@Component
public class RedisIdWorker {
    private static final long BEGIN_TIMESTAMP=1640995200L;
    /**
     * 序列号的位数
     */
    private static final int COUNT_BITS=32;

    private StringRedisTemplate stringRedisTemplate;

    public RedisIdWorker(StringRedisTemplate stringRedisTemplate){
        this.stringRedisTemplate=stringRedisTemplate;
    }
    public long nextId(String keyPrefix){
        //1.生成时间戳
        LocalDateTime now=LocalDateTime.now();
        long nowSecond=now.toEpochSecond(ZoneOffset.UTC);
        long timestamp=nowSecond-BEGIN_TIMESTAMP;

        //2.生成序列号
        //2.1获取当前按日期，精确到天
        String date=now.format(DateTimeFormatter.ofPattern("yyyy:MM:dd"));
        //2.2自增长
        long count=stringRedisTemplate.opsForValue().increment("icr:"+keyPrefix+":"+date);

        //3.拼接并返回
        return timestamp<<COUNT_BITS|count;
    }
}
